The present invention relates to document feeding along a document feed path, and is particularly directed to a document feeder for feeding a document along a document feed path in a document processing system such as a bank check processing system.
Many different types of document feeders are known. Some known document feeders include a document feeder tray of the inclined type in which a stack of documents to be fed to a document feeding mechanism is placed on an inclined surface. The document feeding mechanism processes the stack of documents by picking the documents one-by-one from a lower end position of the stack of documents. Typically, a weight resting on the stack of documents rolls or slides along the inclined surface to advance the stack of documents towards the document feeding mechanism. A disadvantage in using a document feeder tray of the inclined type is that the weight of the stack of documents varies with the size of the stack. As the documents are being fed, the size of the stack decreases. Accordingly, the weight of the stack decreases as documents are being fed.
Another known type of document feeder tray is of the horizontal type in which a stack of documents to be fed to a document feeding mechanism is placed on a horizontal surface. The document feeding mechanism processes the stack of documents by picking the documents one-by-one from one end of the stack of documents. Typically, a spring-biased plate is disposed at the other end of the stack of documents to advance the stack of documents towards the document feeding mechanism. A disadvantage in using a document feeder tray of the horizontal type and a spring-biased plate which advances a stack of documents contained in the document feeder tray is that the spring characteristics change over time due to normal wear and tear of the spring.